const conn = require('../app/database')
const {APP_HOST, APP_PORT} = require('../app/config')

class MomentService {
  // 创建动态
  async create(userId, content) {
    const statement = `INSERT INTO moment (user_id, content) VALUES (?, ?);`
    const result = await conn.execute(statement, [userId, content]) 
    return result[0]
  }

  // 获取某一条动态
  async getMomentById(momentId) {
    const statement = `
      SELECT 
        m.id id, m.content content, m.createAt createTime, m.updateAt updateTime,
        JSON_OBJECT('id', u.id, 'name', u.name, 'avatarUrl', u.avatar_url) user,
        IF(COUNT(l.id),JSON_ARRAYAGG(
          JSON_OBJECT('id', l.id, 'name', l.name)
        ),NULL) labels,
        (SELECT IF(COUNT(c.id),JSON_ARRAYAGG(
          JSON_OBJECT('id', c.id, 'content', c.content, 'commentId', c.comment_id, 'createTime', c.createAt,
                      'user', JSON_OBJECT('id', cu.id, 'name', cu.name, 'avatarUrl', cu.avatar_url))
        ),NULL) FROM comment c LEFT JOIN user cu ON c.user_id = cu.id WHERE m.id = c.moment_id) comments,
        (SELECT JSON_ARRAYAGG(CONCAT('${APP_HOST}', ':', '${APP_PORT}', '/moment/images/', file.filename))
        FROM file WHERE m.id = file.moment_id) images
      FROM moment m
      LEFT JOIN user u ON m.user_id = u.id
      LEFT JOIN moment_label ml ON m.id = ml.moment_id
      LEFT JOIN label l ON ml.label_id = l.id
      WHERE m.id = ?
      GROUP BY m.id; 
    `
    const result = await conn.execute(statement, [momentId]) 
    return result[0]
  }

  // 获取用户动态列表
  // 涉及分页查询
  async getMomentList(offset, size) {
    const statement = `
      SELECT 
        m.id id, m.content content, m.createAt createTime, m.updateAt updateTime,
        JSON_OBJECT('id', u.id, 'name', u.name) user,
        (SELECT COUNT(*) FROM comment c WHERE c.moment_id = m.id ) commentCount,
        (SELECT COUNT(*) FROM moment_label ml WHERE ml.moment_id = m.id) labelCount,
        (SELECT JSON_ARRAYAGG(CONCAT('${APP_HOST}', ':', '${APP_PORT}', '/moment/images/', file.filename)) 
        FROM file WHERE m.id = file.moment_id) images
      FROM moment m
      LEFT JOIN user u ON m.user_id = u.id
      LIMIT ?, ?;
    `
    const result = await conn.execute(statement, [offset, size]) 
    return result[0]
  }

  // 修改动态
  async update(momentId, content) {
    const statement = `UPDATE moment SET content = ? WHERE id = ?;`
    const result = await conn.execute(statement, [content, momentId])
    return result[0]
  }

  // 删除动态
  async remove(momentId) {
    const statement = `DELETE FROM moment WHERE id = ?;`
    const result = await conn.execute(statement, [momentId])
    return result[0]
  }

  // 判断标签是否与动态有关联
  async hasLabels(momentId, labelId) {
    const statement = `SELECT * FROM moment_label WHERE moment_id = ? AND label_id = ?;`
    const [result] = await conn.execute(statement, [momentId, labelId])
    return result[0] ? true : false
  }

  async addLabels(momentId, labelId) {
    const statement = `INSERT INTO moment_label(moment_id, label_id) VALUES (?, ?);`
    const result = await conn.execute(statement, [momentId, labelId])
    return result[0]
  }

}


module.exports = new MomentService()
